"+":
classified by occupation; 100 %, if classified by test
"*": classified only by IQ; classification by occupation gives about 55%; n = 820.
"#": some cousins were still to young and did not have full opportunity to become distinguished
"-": no data
Sources:

Galton, Francis: Hereditary Genius. London 1869.100 famous men (n = 43) of science (mathematics and natural sciences) have famous male relatives.

Brimhall, Dean, R.: Family resemblances among American men of science.
The American Naturalist 56 (1922) 504-547; 57 (1923) 74-88, 137-152, and 326-344.
In 1915 questionnaires were filled in by 956 distinguished American men of science and their relatives.